The Intellectual and Thematic Landscape of Waste Lubricant Oil Management Research through a Combined Bibliometric Analysis and Systematic Literature Review (SLR)

Abstract

This study systematically maps the intellectual and thematic landscape of Waste Lubricant Oil (WLO) management research by combining bibliometric analysis and a Systematic Literature Review (SLR) using the TCCM (Theory-Context-Characteristics-Methodology) framework. The research acknowledges the profound shift in WLO management—from a pollution-control problem to a crucial resource recovery imperative aligned with the circular economy. The bibliometric analysis of 215 unique documents published between 2000 and 2025 reveals a mature and expanding field, with a notable surge in production after 2015 and rising influence from emerging economies like South Africa and China. The field is primarily anchored in two interconnected thematic clusters: tribological performance (for example, rolling oil, friction) and environmental sustainability (for example, recycling, regeneration). The SLR component, synthesizing 59 selected studies, confirms the field's grounding in theories of life-cycle assessment (LCA), industrial symbiosis, and green chemistry. Contextually, the research spans industrial applications (steel, energy) and environmental remediation. Methodologies predominantly include experimental designs for regeneration (solvent extraction, membrane separation) and thermo-chemical conversion (pyrolysis, hydrocracking), increasingly supported by pilot-scale validation and systems-level modelling (LCA, MCDA) for sustainability optimization. The combined approach provides a holistic understanding of WLO management as a critical frontier for advancing cleaner production, energy efficiency, and circular economy practices. In this paper a section has been specifically devoted for policy implications to promote circularity in waste lubricant oil management.